THE combination of reliability and mechanical simplicity has helped to make flail chain type rotary machines popular, but it may also be one reason why routine maintenance is often skimped says Peter Mason, service engineer for Dowdeswell Engineering.

"As there isnt much to go wrong some people assume they dont need any maintenance," he said. "Another reason why they get neglected is that they are always mucky. Working on a spreader is not a popular job, but they are all right if you clean them up a bit before starting work."

First stop on Peter Masons maintenance checklist was the pto drive shaft, one of the important safety items. The guard and its retaining chains must be in good condition and cover the full length of the joints and shaft, and guard tubes must slide freely.

At this point Peter Mason also checked the drive joints for damage and lubrication. There was no fault with the lubrication – in fact this spreader showed plenty of evidence of regular attention from the grease gun – but the joint at the tractor end of the shaft was damaged.

Cause of damage

The cause? Turning too sharply with the pto engaged. A new joint should be fitted before the next big spreading stint.

Other safety items include wheels and tyres. Wheel nuts need checking to make sure they are tight, particularly during the first two years of a new spreaders working life or after a wheel has been removed for a puncture repair. Nuts work lose more often than many people realise, and if they are not tightened the threads may be damaged.

Muck spreaders on public roads must comply with the regulations about tread depth and general condition, so check both tyres. If the casing is damaged it is more likely to cause a puncture or blow-out when the spreader is loaded, and this makes tyre changing difficult and time consuming.

If in doubt, replace the tyre before using the machine again, as this could save time and trouble later. Use a gauge to check that tyre pressures are in line with the makers recommendations.

A faulty or badly adjusted parking brake could also be a safety hazard which needs checking as part of the maintenance routine. The ratchet should work freely when the hand lever is moved, and the brakes should be fully applied well before the lever reaches the end stop. Brake adjustment is by means of a screw at the end of the brake operating rod.

If a flail chain flies off when the spreader is working it could be dangerous. This is a rare occurrence and to ensure it does not happen more frequently, chains must be checked to make sure each end link is firmly gripped by the clevis on the rotor.

If a link moves in its clevis there will be excessive wear which could lead to a lost chain. Use a ratchet spanner to tighten loose clevis nuts.

Flail chains should be perfectly balanced on the rotor, and a missing chain must be replaced before using the machine again to avoid the excessive wear of an unbalanced rotor. If square end plates are fitted, these should also be evenly distributed to keep the balance right.

When each chain is fully extended it should be at least 0.75in away from the inside surface of the drum, and a smaller gap means the chain has stretched and needs replacing. Shortening the chain by replacing one link by a nut and bolt is not recommended unless a high tensile bolt is used. If stretched chains are not dealt with they will eventually cut the drum – and a replacement is expensive.

The starter flails at each end of the rotor should move freely, but a frequent problem is accumulated muck and bale string which must be cleared. Fen Farms spreader was almost free of bale string, indicating that care is taken to keep string out of the bedding straw.

Turning by hand

After turning the rotor by hand to make sure the front and back bearings move freely and smoothly, the next area to check was the chain and sprocket drive to the rotor. With the guard removed, Peter Mason checked for grease on the chain and sprockets and measured the chain tension.

As the movement was slightly over the 0.5in limit he loosened the nuts holding the bottom sprocket, used the screw adjustment to tension the chain, then tightened the nuts again and replaced the guard.

Final stage in the maintenance routine is to use the grease gun and oil can as indicated in the Sidespreader lubrication chart – and then its ready for work again.

"This Sidespreader appears to get a lot of work, but apart from the drive joint damage and one or two loose clevis nuts it is well maintained," said Peter Mason. "Even the wooden strip protecting the loading lip shows little damage, and this suggests that someone uses the muck fork very carefully."

This Dowdeswell 1555 sidespreader is the type of spreader renowned for its mechanical simplicity – it still needs regular maintenance, though.

Lower link arms are often the cause of pto shaft failure, second only to tight turns with the shaft engaged. Check and replace as necessary.

Check flail chain nuts are tight – should the bolt let go, chain will travel a good distance.